Heads Up Display

This is my first "3d" game, so I apologize for all the questions in an absurdly quick succession.

Anyways, I have the 3d engine somewhat set up, but now I want to draw a bunch of stuff on top to indicate various player status information.

What I'm thinking is:

...
//draw the 3d environment
...
//draw on top of all that
glDisable(GL_DEPTH_TEST);
glOrtho2d(0,800,0,600);
..

then start drawing. The reason I'm asking is I'm going to implement it tomorrow and would rather avoid any unnecessary bugs. Does this seem like a good method? Do I need to "LoadIdentity" on the "Modelview" matrix before I call glOrtho2d?